Fresh produce is harvested and packaged so that it can be stored and transported to arrive in a fresh condition at remote destinations. Iceberg lettuce, for example, is manually cut and placed by hand in a pre-formed standard lettuce bag that is vented to promote effective vacuum cooling. The bag is manually taped closed, and twenty-four to thirty heads of the bagged lettuce are packed in cases to achieve a minimum gross carton weight of about fifty pounds. This process typically requires a team of twenty-four to twenty-eight people organized into groups of two cutters and one taper/packer. A team can pack an average of two hundred fifty cases per hour on an average production day. The teams work behind a harvester machine comprising two elongate wings projecting from opposite sides of a trailer, with each wing incorporating a plurality of bagging and taping stations. The machine is moved through a lettuce field in spanning relation to rows of lettuce, which is harvested by the team as the machine advances through the field. This method of harvesting iceberg lettuce has remained basically unchanged over the past thirty years.
The cartons of bagged lettuce are palletized by hand, put on a trailer, and sent to a plant to be vacuum cooled prior to storage in a cold storage facility and subsequent shipment to a point of sale, where the bagged lettuce will arrive fresh and ready for display and sale.
Efforts have been made in the prior art to at least partially automate the process of harvesting and bagging lettuce, as exemplified, for example, by U.S. Pat. No. 3,245,198 to Schmied, U.S. Pat. No. 3,851,440 to Horsky, U.S. Pat. No. 4,525,983 to Libow, and U.S. Pat. No. 5,794,410 to Harper. These patents all relate to at least partially automated bagging equipment which functions to push a head of lettuce against a plastic film wrap so that the head of lettuce is enclosed by the wrap, rotate the bagged head of lettuce to twist and gather excess wrap material above the head of lettuce, sever the wrap above the twisted portion, and then heat seal it by applying heat to the gathered twisted portion of wrap. Although these prior art systems should help reduce the labor requirements of harvesting and bagging lettuce, they are not entirely satisfactory because they either use too much material, and/or produce an unsightly package, and/or take an excessive amount of time due to the steps required, and/or damage the produce by applying heat and/or excessive force to it.
To date, no commercially viable packaging system has been designed to address the packer's desires for increased productivity, reduced labor costs, improved package appearance, and reduction in the amount of plastic used.